The 400 kg blue dye that CōBō has used is pure organic material.
It was inherited from the Edo Period called the natural lye fermentation.
It is the traditional technique from ancient times.
The blue dye contains indigo dye, scum, sake, limes, wheat bran and water.
Persicaria tinctoria is a plant and a main source of Japanese indigo dye.
However, it was illegal to plant in WWII.
However, once the Persicaria tinctoria stopped being planted it became in danger of going extinct.
Therefore, to avoid the soldiers, a family that still planted Persicaria tinctoria in the forest of Tokushima
and keeped its seed is the blue dyeing master in Sato family,
Mr. Akihito Sato’s father and his cousin, Tsuyako Iwata.
If a soldier noticed this, the entire family would put their lives at risk.
Even though they sacrificed their life for protecting white flowers called （Shirobana kojouko)白花小上粉,
the Sato family is still planting to this very day.
Normally the flower– Polygonum tinctorium is red, but the one in the Soto family is white.
This is evidence of protecting the endangered plant by sacrificing their life, says Mr. Akihito Sato.
Protecting this tradition is extremely important.
These valuable seeds need around 300 days from planting, harvesting, making to ferment,
and tuning to the useable blue dye.
The master would keep the fresh blue dye for a year, then fermented the blue dye until becoming useable.
Before enabling the blue dye process, it requires long time and a great technique.
This is really important for us, and we will not treat this casually.
Therefore, we persist by using purely organic materials and traditional methods to extract and produce the blue dye.
Masters including ours who make the blue dye are all devoted with keeping the classical techniques on hold.
In my view, this is my responsibility to preserve this culture and pass this on to the next generation.